1. Field of the Invention
This invention relates generally to deposition shields for processing chambers, including for example physical vapor deposition or sputtering chambers, chemical vapor deposition chambers and ion implantation chambers. More specifically, the invention relates to a deposition shield assembly for protecting an electrostatic chuck from the deposition species during semiconductor wafer processing.
2. Description of the Background Art
In deposition processes, species from a source such as a target, a gas inlet manifold and the like may deposit on exposed internal chamber surfaces, including the chamber walls and hardware. Shields are available which are designed to intercept such species. However, the presently available shields have not been successful in completely blocking unwanted deposition on these surfaces. Also, such shields may be difficult and/or time-consuming to replace, and require relatively frequent replacement. The use of automatic substrate exchange systems, with their attendant in-chamber movable components, increases the difficulty of attaining adequate shielding and easy replacement of these shields.
Furthermore, recent developments in high temperature semiconductor processing, such as high temperature physical vapor deposition (PVD), have begun using substrate support and retention pedestals that contain electrostatic chucks. The performance of such chucks is substantially reduced if the chuck is exposed to the deposition species. The interference with chuck performance is especially pronounced when the deposition species is a metal such as copper. Furthermore, sustained exposure to the deposition species may contaminate the chuck to such an extent as to make the chuck inoperative. Consequently, it is imperative that none of the surfaces of the chuck be exposed to the deposition species.
Therefore, there is a need in the art for shields that provide adequate shielding for an electrostatic chuck.